Although I know some would disagree, personally I find them to sound quite similar. Which is the better deal for you is really dependant on your music preferences. Both are dark-sounding cans with a fantastic midrange (the K240S has a slight edge in this regard). Bass on the K271 is similar sounding, but better defined/more controlled. There's a significant amount more bass on the K240, but I still think the K271 has slightly more bass than what I would consider 'neutral' for their sound signature. Detail is significantly better on the K271 in all respects (bass, mids, trebles). The K240 is airier-sounding since they're not a fully-closed design. All this said, the K271 is a much more all-around headphone than the K240S is. I can listen to just about anything with the K271; the K240 only works with certain genres (most notably rock, jazz, and hip-hop). If you listen to a lot of electronic or classical music I cannot recommend the K240S. Hope this helps.